1、创建三个视图控制器 FirstViewController、SecondViewController、ThirdViewController
2、在FirstViewController.swift中viewDidLoad添加 self.title = “Item #1” self.tabBarItem.image = UIImage(named：“Tab1”) let label = UILabel(frame：CGRect(x：40, y：150,width：240, height：44)) label.text = “第一页” label.textAlignment = NSTextAlignment.center label.font = UIFont(name：“Arial”, size：36) self.view.addSubview(label)
3 AppDelegate.swift的didFinishLaunchingWithOptions方法： let firstViewController = FirstViewController() let secondViewController = SecondViewController() let thirdViewController = ThirdViewController() let tabViewController = UITabBarController() tabViewController.viewControllers =[firstViewController, secondViewController,thirdViewController] self.window?.rootViewController = tabViewController
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加右上角提醒：self.tabBarItem.badgeValue="8"
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手动改变tab
1 let button = UIButton(frame：CGRect(x：40, y：220, width：240, height：44)) 2 button.setTitle(“进入第二页”, for：UIControlState()) 3 button.backgroundColor = UIColor.black 4 button.addTarget(self, action：
selector(FirstViewController.enterPage2),
for：.touchUpInside) 5 self.view.addSubview(button) 1 func enterPage2() 2 { 3 self.tabBarController？.selectedIndex = 1 4 }
可以改变导航栏的位置：
let screenWidth = UIScreen.main.bounds.width tabViewController.tabBar.frame = CGRect(x：0, y：0,width：screenWidth, height：44)
隐藏顶部状态栏
info.plist中Status bar is initially hidden=YES View controller-based status bar appearance=NO
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